linux-kernel - [Bug] "BUG: soft lockup in perf_event

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Message-ID: <CAP=Rh=PtKsiXGLYeK5tr4LSw-AHJ6LM4kuTWR3Hs5sQQp02wCw@mail.gmail.com>
Date: Wed, 21 May 2025 21:49:41 +0800
From: John <john.cs.hey@...il.com>
To: Josh Poimboeuf <jpoimboe@...nel.org>, Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: [Bug] "BUG: soft lockup in perf_event_open" in Linux kernel v6.14

Dear Linux Kernel Maintainers,

I hope this message finds you well.

I am writing to report a potential vulnerability I encountered during
testing of the Linux Kernel version v6.14.

Git Commit: 38fec10eb60d687e30c8c6b5420d86e8149f7557 (tag: v6.14)

Bug Location: 0010:orc_find arch/x86/kernel/unwind_orc.c:217

Bug report: https://pastebin.com/QzuTF9kT

Complete log: https://pastebin.com/XjZYbiCH

Entire kernel config: https://pastebin.com/MRWGr3nv

Root Cause Analysis:

A soft lockup occurred on CPU#0 in the unwind_next_frame() function
during stack unwinding triggered by arch_stack_walk().
This was called in the middle of __kasan_slab_free() as part of RCU
reclamation path (rcu_do_batch()), likely triggered by a SLAB object
free in SELinux's avc_reclaim_node().
The system was under heavy AVC pressure due to continuous audit and
avc_has_perm() calls (e.g., from selinux_perf_event_open), leading to
repeated avc_node allocations and reclamations under spinlocks.

At present, I have not yet obtained a minimal reproducer for this
issue. However, I am actively working on reproducing it, and I will
promptly share any additional findings or a working reproducer as soon
as it becomes available.

Thank you very much for your time and attention to this matter. I
truly appreciate the efforts of the Linux kernel community.

Best regards,
John